Provided herein are devices and methods for driving and controlling industrial processes using inherent kinetic energy of a fluid that is an integral part of the industrial process. In this manner, the environmental impact from the industrial process is significantly reduced and revenue to the producer increased, while maintaining and even increasing reliability and efficiency.
Processes and systems are disclosed herein for recovering hydrocarbon vapors that are “flashed” from a liquid phase in an industrial process. These processes and systems are useful in an industrial process relating to hydrocarbon vapor recovery units (VRU) for use in a variety of hydrocarbon recovery applications. In particular, applications provided herein include hydrocarbon vapor recovery from a liquid phase in a separation facility, natural gas plant, offshore oil rig, or numerous other petroleum recovery facilities and refineries. Hydrocarbon, natural gas or petroleum vapors exist when petroleum or natural gas is recovered from wells. The vapor, or as often more generally referred to as “natural gas”, does not remain entrained in the hydrocarbon liquids recovered from the well, but instead is released due to decreasing pressures, increasing temperatures (such as by ambient temperature changes or from a heat exchanger), or agitation.
Lighter molecular weight hydrocarbons (“light ends”, C1-C3, etc. . . . ) “flash” or escape equilibrium with the liquids or natural gas liquids (“heavy ends”, C6+) in equipment such as storage tanks, low pressure separators, low and high temperature separators, to only name a few general onshore pieces of equipment. Instead of recovering this gas, it is often vented or incinerated in a combustor, leading to significant monetary loss of a potential revenue stream and significant adverse environmental and health impacts.
One reason why these hydrocarbon gases are not readily recovered is that the pressure differential between the flash gas and the sales line is too great. Often, as is the case with storage tanks, the pressure difference can be 400 psi or more. Most current VRU solutions require either electric or gas powered (natural gas or gasoline) engines to drive compressors.
Gas-powered processes, however, suffer from a number of drawbacks, including environmental and operational disadvantages. With respect to environmental factors, although natural gas (specifically methane) emissions account for a lower overall percentage of all greenhouse gasses, the Global Warming Potential (GWP) of methane determined by EPA models is 21 times greater than CO2, the most abundant greenhouse gas. The health effects of hydrocarbon emissions are also considered to be highly dangerous. Accordingly, there is a need in the art to replace hydrocarbon gas-powered processes with more environmentally responsible processes.
With respect to operational disadvantages and constraints, electric or gas-powered (natural gas or gasoline) driven compressors require components that can be very costly to purchase, operate and maintain. Furthermore, remote drilling sites may not have electric hook-up. Running gas-powered devices to recover hydrocarbon gas reduces the hydrocarbon end-capture, decreases economic yield and decreases capture efficiency. Maintenance can become an issue for both electric and gas powered systems, which is further compounded by sites that are not readily accessible. For example, all the same issues exist in a multitude of facilities including plants and offshore drilling rigs. Accordingly, the processes and systems for powering a compressor without electric or gas power are relevant for VRU applications.
As discussed herein, the problem of powering a compressor without electric or gas power is addressed by utilizing the kinetic energy inherent in a pressurized fluid flow in the industrial process (e.g., natural gas, petroleum, or water from the wellhead, separators, sales lines, pipelines, etc.) to drive a boundary-layer disk turbine (BLDT), which in turn mechanically drives a compressor pump. This provides a cost-effective, elegant, clean/green and robust solution to compressor power problem.